1). Field of the Invention
This invention relates to a method of constructing an electronic assembly and to an electronic assembly which may be made according to the method of the invention.
2). Discussion of Related Art
Integrated circuits are formed on semiconductor wafers. The wafers are then sawed into semiconductor chips also known as microelectronic dies. Each semiconductor chip is then mounted to a package substrate. An integrated circuit within the semiconductor chip can be powered up and data signals can be sent to and received from the integrated circuit via the package substrate.
When the integrated circuit is powered up, heat is generated on the semiconductor chip which could cause destruction of the integrated circuit if the heat is not transferred away. A thermally conductive plate, such as a heat spreader or a heat sink, is often located next to the semiconductor chip. A thermally conductive grease may be located between the semiconductor chip and the thermally conductive plate. The thermally conductive grease contacts the semiconductor chip and the thermally conductive plate on opposing sides and acts as a thermal interface between the semidonductor chip and the thermally conductive plate. Heat can then be transferred from the semiconductor chip through the grease to the thermally conductive plate, from where heat can be transferred to a heat sink or other device and can be convected into the ambient.
The use of grease as a thermal couple is often unsuitable for high power applications. A thermally conductive grease has a relatively low thermal conductivity and thus provides a substantial thermal barrier for heat transferring from the die to the thermally conductive plate. As a result, an insufficient amount of heat is transferred to the heat spreader or heat sink when a large amount of heat is generated on the semiconductor chip.